Answer:
We have to add 1.86 L of water to make the solution 7% saline.
Step-by-step explanation:
The concentration of a saline solution is given by
C(x) = 
where x represents the amount of water used to dilute the solution.
We have to find how much water must be added to obtain a solution that is 7% saline.
If we see the equation we notice that as we add the value of x, the concentration of the solution decreases.
Here C(x) = 0.07
0.07 = 
Rearranging,
1 + x = 
1 + x = 2.86
x = 1.86 L
We have to add 1.86 L of water to make the solution 7% saline.
Answer:
D
Step-by-step explanation:
When f(x) is equal to 0, x=4.
See attached photo for solution
(4x - 10) + (12x + 6) = 68
16x - 4 = 68
16 x = 72
x = 4.5
So, 12 (4.5) + 6 = 60